It has been estimated that developmental disabilities affect 10% of all families in the USA. Researchers are urgently needed who are willing and able to apply modern research methods to elucidating the pathogenesis and pathophysiology of these disorders, so that new and more effective therapeutic interventions can be identified. The aim of our interdisciplinary Institutional Post-doctoral Training Program in Neurodevelopmental Disabilities, based at The Children's Hospital of Philadelphia (CHOP) and The University of Pennsylvania (U of P), is to train MD and PhD post-doctoral fellows in research focused on genetic and acquired disorders that cause mental retardation and developmental disability. Nineteen Mentors will participate in this first competitive renewal of this program; 13 are based primarily at CHOP, and 6 primarily at the U of P. All are heavily involved in biomedical graduate education and are closely interlinked by mutual research projects and grants. In addition to mentored research training, our curriculum emphasizes a clinical practicum requirement for both MDs and PhDs, formal course work through the U of P Graduate Studies Program, and training in bioethics, biostatistics, and skills in scientific writing and presentation. During the first 4 years of our program, we accepted 8 Trainees, of whom 2 were MDs, 5 PhDs, and 1 and MD/PhD. Of the 5 who have thus far completed our program, 2 have obtained junior faculty positions, 2 have entered clinical training programs (1 in neurology, 1 in neurosurgery) prior to returning to an academic career, and 1 accepted a position in a biotechnology firm. Two additional Trainees will complete our program during the coming year; each has been offered and accepted a medical school assistant professorship (1 in Neurology and Pediatrics, U of P, the other in Psychiatry, UCLA). We were approved for 4 post-doctoral fellows/year during our first 5 years, and request the same level of funding for the next 5 years. [unreadable] [unreadable]